Abstract
D2O treated sepiolite and-palygorskite were studied by DTA, TG and EGA. The adsorption was carried out by wetting the clays with D2O prior and after heating sepiolite to 430 and 600°C, and palygorskite to 360 and 600°C. Optimal conditions for adsorption of D2O are obtained after the temperate heating. Heating to 600°C blocked the porous structure and the adsorption took place on the external surface. Gas evolution curves showed that HDO is evolved during the recrystallization stage of sepiolite but not of palygorskite. It appears that during the first stages of dehydroxylation of sepiolite deuterium is trapped by the amorphous meta sepiolite and is released at higher temperatures during the recrystallization stage. It was concluded that the second stage of dehydroxylation of sepiolite is not associated with the decomposition of residual TOT units but results from the decomposition of secondary units which have been formed during the first stage of the dehydroxylation of this clay.
Original language | English |
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Pages (from-to) | 291-297 |
Number of pages | 7 |
Journal | Thermochimica Acta |
Volume | 135 |
Issue number | C |
DOIs | |
State | Published - Oct 1988 |